Scala on MAC(2)Scala IDE Version and Environment Prepare
1. Some Tools to prepare
Spring Tool Suite - 3.1.0
http://www.springsource.org/downloads/sts-ggts

Typesafe Scala IDE - 2.1-M2-2.9
http://typesafe.com/stack/scala_ide_download

Eclipse - 4.2.1
http://www.eclipse.org/downloads/
eclipse-jee-juno-SR1-macosx-cocoa-x86_64

Scala  - 2.10.0
http://www.scala-lang.org/downloads

2. Prepare Scala
Just unzip the scala and put it in my tool directory
/Users/carl/tool/scala-2.10.0

Since I already have scala 2.9.2 on my pc, so I will do like this.
>sudo ln -s /Users/carl/tool/scala-2.9.2 scala2.9.2
>sudo ln -s /Users/carl/tool/scala-2.10.0 scala2.10.0

Delete my old directory link
>sudo rm scala

Update it to the latest one
>sudo ln -s scala2.10.0 scala

Check the version
>scala -version
scala code runner version 2.10.0

3. Prepare Eclipse
TypeSafe eclipse
Right now, I plan to use TypeSafe eclipse, only because it is small
I plan to install the plugin from here:
http://download.scala-ide.org/sdk/e37/scala210/dev/site/

I pick up the URL from this website:
http://scala-ide.org/download/milestone.html

Maybe, if we use other version of eclipse, we need to change the plugin URL.

It is working on type safe eclipse Scala IDE

Spring Tool Suite
Install the default Scala plugin on dashboard first.
The scala version is 2.9.3. It is not right for me. I will change it.
Firstly, uninstall the old 2.9.3 plugin. Then use this URL for STS 3.10.0

http://download.scala-ide.org/sdk/e38/scala210/dev/site/

It works.

In STS, there is already git plugin. So it is good for me. So I will go to 'Git Repository Exploring' view and choose 'Add an existing local Git repository'

4. Some project Tips
Build to eclipse based on SBT
Create a file ~/.sbt/plugins/build.sbt
addSbtPlugin("com.typesafe.sbteclipse" % "sbteclipse-plugin" % "2.1.0")

>sbt eclipse

or
>sbt
sbt>update
sbt>eclipse

References:
http://www.springsource.org/downloads/sts-ggts
http://sillycat.iteye.com/blog/1725920